A Techno-Economic Feasibility Study For Establishing An Ethane-Plus Recovery Unit From The Imported LNG Through The Regional LNG/NG Trading Hub

Abstract

The high concentrations of ethane and heavier components (C2+ up to 7 mol %) in the LNG which Egypt imported during 2015:2019 (stopped since 2019) represent an attractive motivation to study recovery of these heavier components which considered source of feedstock to the petrochemicals industry in Egypt. These quantities of ethane and heavier hydrocarbons are considered adequate quantities for processing and recovery of valuable products rather than being utilized in the national NG grid. Over and above, Egypt intends to expand and participate in the global LNG trade market via establishing an international LNG/ NG trading hub which means increase in the imported LNG volume with variable HCs concentrations during the year. From this perspective, it becomes increasingly important to achieve the maximum benefit of the expected LNG/ NG hub via developing an ethane-plus recovery unit to recover ethane and heavier HCs (C2+) from LNG which is considered an essential feedstock to petrochemical plants for the production of LPG, Ethylene, Propylene and polyethylene which help the petrochemical sector in bridging the gap between demand and supply of petrochemical products in Egypt.

The present study deals with studying the technical and economic feasibility of establishing an ethane-plus recovery unit to recover ethane and heavier HCs from the imported LNG through the proposed international LNG/ NG trading hub. As difference in price between selling C2+ as a liquid product, or as fuel is known as "shrinkage value,” as selling these valuable products mixed in the natural gas is less profit than separated from natural gas and selling as single components as these valuable products have higher selling price than sales gas. This indicates the desired recovery level by the gas process.

The process design objectives of the proposed recovery unit will include maximizing the production of C2/C3 mix, commercial propane and LPG by studying some of NGL separation processes, while as some processes lack the flexibility of receiving various feed compositions (specs according to contracts), thereby leading to an unstable operation in the liquid natural gas (LNG) receiving terminal. Based on the analysis of imported LNG’s composition statistical data in Egypt, this thesis proposes a techno-economic comparison and analysis of three schemes of Ethane-plus recovery processes for quantities of LNG imported through LNG/NG trading hub (500 MMSCFD) under two cases (lean & rich) of typical LNG feed-in composition. In response, the selected proper optimum NGL recovery process is proposed, and a techno-economic study and an estimate of the IRR and payback period for all scenarios of LNG compositions imported through the LNG/NG hub are conducted. Process simulation of the recovery unit is created on the HYSYS simulation software with different process schemes and different compositions of LNG, including the equipment required, operating conditions and the unit capital and operating cost.

The comparison results reveal that the process scheme 1 has the best economic benefit for specific performance: the net profit of scheme 1 as compared to the other two schemes is as high as 2.5% which makes the net profit adequate and its total investment cost is 10 % lower than that of scheme 2 and its IRR is also the shortest. In contrast, scheme 2 has the worst economic benefit, and the longest investment recovery period; however, it has the highest recovery, due to increase in fuel and power consumption which negatively affects its operating cost. In conclusion, process scheme.1 can be economically and efficiently used in Egypt LNG receiving terminal, thereby generating the flexibility to receive multiple feed composition.

The results of the present study will have concluded selection of the most proper feasible process technology to recover variable compositions of ethane and heavier hydrocarbons from the imported LNG through the international LNG/ NG trading hub. Also, the study showed that using these techniques will recover significant quantities of ethane and heavier components from the imported LNG which will play an important role in supplying the petrochemical feedstock, providing continuity to petrochemical plants, saving hard currencies and helping in closing the gap between production and consumption of petrochemical products in Egypt.

The high concentrations of ethane and heavier components (C2+ up to 7 mol %) in the LNG which Egypt imported during 2015:2019 (stopped since 2019) represent an attractive motivation to study recovery of these heavier components which considered source of feedstock to the petrochemicals industry in Egypt. These quantities of ethane and heavier hydrocarbons are considered adequate quantities for processing and recovery of valuable products rather than being utilized in the national NG grid. Over and above, Egypt intends to expand and participate in the global LNG trade market via establishing an international LNG/ NG trading hub which means increase in the imported LNG volume with variable HCs concentrations during the year. From this perspective, it becomes increasingly important to achieve the maximum benefit of the expected LNG/ NG hub via developing an ethane-plus recovery unit to recover ethane and heavier HCs (C2+) from LNG which is considered an essential feedstock to petrochemical plants for the production of LPG, Ethylene, Propylene and polyethylene which help the petrochemical sector in bridging the gap between demand and supply of petrochemical products in Egypt.

The present study deals with studying the technical and economic feasibility of establishing an ethane-plus recovery unit to recover ethane and heavier HCs from the imported LNG through the proposed international LNG/ NG trading hub. As difference in price between selling C2+ as a liquid product, or as fuel is known as "shrinkage value,” as selling these valuable products mixed in the natural gas is less profit than separated from natural gas and selling as single components as these valuable products have higher selling price than sales gas. This indicates the desired recovery level by the gas process.

The process design objectives of the proposed recovery unit will include maximizing the production of C2/C3 mix, commercial propane and LPG by studying some of NGL separation processes, while as some processes lack the flexibility of receiving various feed compositions (specs according to contracts), thereby leading to an unstable operation in the liquid natural gas (LNG) receiving terminal. Based on the analysis of imported LNG’s composition statistical data in Egypt, this thesis proposes a techno-economic comparison and analysis of three schemes of Ethane-plus recovery processes for quantities of LNG imported through LNG/NG trading hub (500 MMSCFD) under two cases (lean & rich) of typical LNG feed-in composition. In response, the selected proper optimum NGL recovery process is proposed, and a techno-economic study and an estimate of the IRR and payback period for all scenarios of LNG compositions imported through the LNG/NG hub are conducted. Process simulation of the recovery unit is created on the HYSYS simulation software with different process schemes and different compositions of LNG, including the equipment required, operating conditions and the unit capital and operating cost.

The comparison results reveal that the process scheme 1 has the best economic benefit for specific performance: the net profit of scheme 1 as compared to the other two schemes is as high as 2.5% which makes the net profit adequate and its total investment cost is 10 % lower than that of scheme 2 and its IRR is also the shortest. In contrast, scheme 2 has the worst economic benefit, and the longest investment recovery period; however, it has the highest recovery, due to increase in fuel and power consumption which negatively affects its operating cost. In conclusion, process scheme.1 can be economically and efficiently used in Egypt LNG receiving terminal, thereby generating the flexibility to receive multiple feed composition.

The results of the present study will have concluded selection of the most proper feasible process technology to recover variable compositions of ethane and heavier hydrocarbons from the imported LNG through the international LNG/ NG trading hub. Also, the study showed that using these techniques will recover significant quantities of ethane and heavier components from the imported LNG which will play an important role in supplying the petrochemical feedstock, providing continuity to petrochemical plants, saving hard currencies and helping in closing the gap between production and consumption of petrochemical products in Egypt.